To make the crust:crush the graham crackers with a rolling pin. You can also use a cup like a rolling pin if you don't have an actual one. Put all the crumblings either into the pie plate--- or into a bowl if you think you might get messy with the next step, because next you are going to mush in the butter/margarine and sugar. Go ahead, use your hands, it's fun. Once the mixture is of an even consistency, press it against the sides and bottom of the pie plate. You want it to be firm enough not to fall to pieces when you cut the pie, so add a tiny bit more butter if you need more cohesion.

To make the filling: put the cream cheese in a bowl and beat it with an electric mixer until it is soft and creamy. Then add the condensed milk, lemon juice, and vanilla extract one at a time, mixing one ingredient completely before adding the next.